@maudlin27 Shield bubbles protect units inside them from AOE attacks hitting the shield, even if the units being protected are in range of the AOE.
AOE attacks can hit more than 1 shield bubble at a time, but think of 'outside' and 'inside' shield bubbles as 2 separate areas.
An AOE attack that hits a shield explodes outside the shield bubble. It can hurt units (or bubbles) outside the bubble, but inside is protected.
Fatboys definitely get protection from artillery fire from parashields. They don't even have to be fully under the bubble - as long as no part of the AOE explosion touches the part of the fatboy that is outside the bubble, the fatboy is fine.
(The larger the AOE of the artillery, the harder it is to hide behind a parashield, but most T2 artillery AOE is nowhere near large enough to make it difficult if the parashield is between the 2. The hardest (the cybran gunther) is conveniently the worst T2 artillery in general due to terrible accuracy and damage!)
Another important factor is this: shots that hit a shield bleed a bit of extra damage into overlapping shield bubbles, even if the overlapping bubbles were not in a place that should be damaged by the attack. For mobile shields, this 'bleed over' bonus damage is much higher.
The bleedover for static shields is - 15%.
The bleedover for mobile shields is 30%.
The bleedover for the fatboy is 0%
This means that shots hitting the fatboy shield do zero 'connected shield' damage to shields inside or overlapping its bubble - they have to actually HIT the parashield bubble to hurt it!
Overall, this effect makes the fatboy shield especially good at 'combining' shields with other units, since the usual penalties, built into the game to prevent many, many shields from being impenetrable, is reduced for fatboys.
(You can see an example of a fatboy being attacked by artillery (from the NE), with a parashield absorbing the hit, here: )
Given that T2 artillery (the most common anti-fatboy tool?) take 20 seconds to reload, and a fatboy can build a parashield every 3.7 seconds, you can see how much build-while-moving can help a fatboy survive artillery. You do have to make sure that the rally point of the fatbctory (!) is in front of the fatboy, but this isn't too hard if you know where you want to be going!
Given that a fatboy has a range not too shy of a T2 artillery, it's hard to really think of good 'test cases' to give examples, but here's one:
If both sides have radar, and a fatboy approaches a bunch of 12 artillery (3 from each faction), reasonably spaced out for efficient defense, the old fatboy would kill ~4 before dying.
The new fatboy (building parashields) kills all 12 and survives.
Of course, in a real game, those artillery would have power generators increasing their firing rate, so don't expect these numbers to translate to a real game.... It's just an example of how much better the new fatboy deals with incoming fire if it's spamming parashields.
(I've not played nearly enough games where I get a chance to make a fatboy, though!)